CVE-2026-73626 JupyterLab before 4.6.2 Authentication Bypass via PyPIExtensionManager
Attackers can bypass extension allowlist/blocklist checks in JupyterLab when custom integrations call install() directly with untrusted input.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-73626?
CVE-2026-73626 is a high-severity authentication bypass vulnerability in jupyterlab, published on 13 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
JupyterLab versions >=4.6.0,<=4.6.1 and <=4.5.9 contain an allowlist/blocklist enforcement gap in PyPIExtensionManager.install(). A missing 'await' caused the is_install_allowed coroutine to never execute, so the extension allowlist/blocklist check was not enforced for direct callers of install(). The stock JupyterLab HTTP API and Extension Manager UI are not affected, as they perform a separate, correctly awaited check. The issue affects only deployments where a custom extension or downstream integration imports PyPIExtensionManager and calls install() directly with a package name influenced by untrusted input, an allowlist/blocklist is configured, the PyPI Extension Manager is enabled, and kernels and terminals are disabled or delegated to remote hosts. Fixed in JupyterLab 4.6.2 and 4.5.10.
Weakness: CWE-284
Which versions are affected by CVE-2026-73626?
5 open source packages ship an affected version, including jupyterlab.
| Package | Affected | Fixed in |
|---|---|---|
jupyterlab Bitnami | All versions | 4.5.10, 4.6.2 |
jupyterlab PyPI | All versions | 4.5.10 |
jupyterlab PyPI | All versions | 4.5.10 |
jupyterlab PyPI | From 4.6.0 | 4.6.2 |
jupyterlab PyPI | From 4.6.0 | 4.6.2 |
How do I fix CVE-2026-73626?
Upgrade jupyterlab to a fixed version for your release line: 4.5.10 or 4.6.2.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-73626 being exploited?
There is no known exploitation of CVE-2026-73626 in the wild and no public exploit code.
Sources
Also known as BIT-jupyterlab-2026-73626, CLEANSTART-2026-LY16502, DEBIAN-CVE-2026-73626, GHSA-r336-hqvq-mfjh, GHSA-whvh-wf3x-g77j, OESA-2026-4167 and 1 more.